Dht22.h

00001 #ifndef DHT22_H
00002 #define DHT22_H
00003 
00004 #include "mbed.h"
00005 
00006 #define DHTLIB_OK                0
00007 #define DHTLIB_ERROR_CHECKSUM   -1
00008 #define DHTLIB_ERROR_TIMEOUT    -2
00009 
00010 /** Class for the DHT22 sensor.
00011  * 
00012  * Example:
00013  * @code
00014  * #include "mbed.h"
00015  * #include "Dht22.h"
00016  *
00017  * Serial pc(USBTX, USBRX);
00018  * Dht22 sensor(PTD7);
00019  * 
00020  * int main() {
00021  *     sensor.read()
00022  *     pc.printf("T: %f, H: %d\r\n", sensor.getFahrenheit(), sensor.getHumidity());
00023  * }
00024  * @endcode
00025  */
00026 class Dht22
00027 {
00028 public:
00029     /** Construct the sensor object.
00030      *
00031      * @param pin PinName for the sensor pin.
00032      */
00033     Dht22(PinName const &p);
00034     
00035     /** Update the humidity and temp from the sensor.
00036      *
00037      * @returns
00038      *   0 on success, otherwise error.
00039      */
00040     int read();
00041     
00042     /** Get the temp(f) from the saved object.
00043      *
00044      * @returns
00045      *   Fahrenheit float
00046      */
00047     float getFahrenheit();
00048     
00049     /** Get the temp(c) from the saved object.
00050      *
00051      * @returns
00052      *   Celsius int
00053      */
00054     int getCelsius();
00055     
00056     /** Get the humidity from the saved object.
00057      *
00058      * @returns
00059      *   Humidity percent int
00060      */
00061     int getHumidity();
00062 
00063 private:
00064     /// percentage of humidity
00065     int _humidity;
00066     /// celsius
00067     int _temperature;
00068     /// pin to read the sensor info on
00069     DigitalInOut _pin;
00070     /// times startup (must settle for at least a second)
00071     Timer _timer;
00072 };
00073 
00074 #endif